Thanks for all the replies and suggestions.
Boroda, yes this would of been helpful, had i known of the option. Other devices still may use the replay gain info though.
"Edit > Preferences > Player > Normalise volume of tracks with replay gain tags"
Hiccup, yes that was my intention just to find all effected files to adjust from one location. virtual tags do allow for filtering "track gain" and i could of made that to make a playlist. Useful for future hunting down of gain adjusted files.
Zak, ha that is buried! Actually it is the opposite of what i was attempting but would allow me to custom tag or flag these, still that's a nice list of things in "Files to Edit" that i didn't realise had a built in option to surface.
In the end [before seeing these replies] i just made a playlist of my library and inbox, added "Track Gain" as a displayed field then sorted by it, selected all effected files and ran restore original volume. It was about 2k+ of tracks affected and was simple enough to do.
Imo all of these solutions [including mine] are a bit of a work around considering the auto-playlist feature allows for almost all metrics to be considered and it's available as a choice when creating custom tags. I still think my suggestion stands as fair [as it seems relatively simple, but i may be wrong].
Out of curiosity the function is referred to in 3 different ways if i'm not mistaken "Volume Leveling" in track properties, "Replay Gain" in some preferences and as "Track Gain" in fields. I can imagine confusion for some users [myself included] if they all all relate to the same setting. Thanks again people, once again such minor nitpicks from me. Cheers =]